I would like to install a block heater for my Volvo MD7A diesel, to aid
with cold starting. Can anyone suggest who might make such a thing?

I would only turn it on maybe an hour or so before I want to start the
engine, so the idea would be to get it from cold to warm as fast as
possible. I'm thinking something in the neighborhood of 1000 watts.

A quick search of the internet, and Ebay, turns up mostly the kind that
you insert into the dipstick, or through a plug into the block.
Neither of these seems like a very good approach for this application,
but I'm not sure what would be better.

Any suggestions would be appreciated.

-Allan